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81.
Ammonia emissions after spreading animal manure contribute a major share to N losses from agriculture. There is an increasing interest in anaerobic co-digestion of liquid manure with organic additives. This fermentation results in a change of physical and chemical parameters of the slurry. Among these are an increased pH and ammonium content, implying a higher risk of NH3 losses from fermentation products. To compare different application techniques and the effect of fermentation on NH3 volatilization, we used the standard comparison method and tested it for reliability. This method seems to be perfectly suited for experiments with a large number of treatments and replicates if prerequisites concerning the experimental layout are considered. We tested four different application techniques on arable and grassland sites. The more the substrate was incorporated into the soil or applied near the soil surface on the grassland site, the less NH3 was lost. Injection of the substrate reduced losses to less than 10% of applied NH4+ on both sites, whereas losses after splash plate application amounted to more than 30%. Trail shoe application on grassland performed as well as injection. Harrowing on arable land also reduced emissions efficiently, if harrowing occurred within the first 2 h after application. Emissions from trail hose-applied co-fermentation product were not greater than from unfermented slurry. Better infiltration of the less viscous substrate seemed to have compensated for the increased loss potential. 相似文献
82.
Corbet DR Dillon K Burnett W Schaefer G 《Environmental pollution (Barking, Essex : 1987)》2002,117(2):337-345
Groundwater from a shallow freshwater lens on St. George Island, a barrier island located in the Panhandle of Florida, eventually discharges into Apalachicola Bay or the Gulf of Mexico. Nutrient concentrations in groundwaters were monitored downfield from three onsite sewage treatment and disposal systems (OSTDS) on the island. Estimates of natural groundwater nutrient concentrations were obtained from an adjacent uninhabited island. Silicate, which was significantly higher in the imported drinking water relative to the surficial aquifer on St. George Island (12.2+/-1.9 mg Si l(-1) and 2.9+/-0.2 mg Si l(-1), respectively), was used as a natural conservative tracer. Our observations showed that nitrogen concentrations were attenuated to a greater extent than that of phosphorus relative to the conservative tracer. At the current setback distance (23 m), both nitrogen and phosphate concentrations are still elevated above natural levels by as much as 2 and 7 times, respectively. Increasing the setback distance to 50 m and raising the drainfields 1 m above the ground surface could reduce nutrient levels to natural concentrations (1.1+/-0.1 mg N l(-1), 0.20+/-0.02 mg P l(-1)). 相似文献
83.
Clemens?J.?Engelke Heike?KnickerEmail author Ingrid?K?gel-Knabner 《Environmental Chemistry Letters》2004,2(2):71-75
Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) was used to reveal the influence of iron on the detectability of condensed tannins extracted from
Picea abies. Iron chloride mixed with condensed tannins suppresses the detection of tannins by MALDI-TOF MS in a dose-dependent manner. Total suppression is observed at concentrations of 250 and 500 mg FeCl3 g–1 of sample. At lower concentrations, spectrum quality is still greatly reduced, but short chain tannins are detected. At 100 mg FeCl3 g–1 of sample, iron increased the intensity of the tannin galloyl ester peaks above those of the corresponding tannin polymers. This points to an antagonistic effect of the galloyl ester moiety on iron complexation with condensed tannins and, thus, their reduced susceptibility to iron interference during MALDI-TOF MS. 相似文献
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Hartmut Koehler Tobias Frische Ingo Dobner Peter Behrend Maike Schaefer Heidi Taubner Bernd Jastorff Jürgen Warrelmann und Ulrich Walter 《Umweltwissenschaften und Schadstoff-Forschung》2001,13(5):291-300
Zusammenfassung Die Befunde des in seiner Konzeption in Teil I dargestellten Freilandexperimentes dokumentieren die TNT-Abreicherung und Erholung
des Standortes im Laufe der Phytoremediation. Das Monitoring umfasst Erhebungen im Feld (Nitroaromatengehalte in Boden, Sickerwasser
und Pflanzen; Erfassung von Bodenorganismen und Streuabbau) und den Einsatz einer Biotestbatterie mit 6 Einzeltests. Die Daten
belegen die hohe Heterogenit?t der TNT-Kontamination, eine rasche initiale Abreicherung und eine geringe Verlagerung von Nitroaromaten
in Pflanzen und Sickerwasser. Die anf?nglich rasche Transformation des TNT zu Aminodinitrotoluolen l?sst nach 3 Monaten deutlich
nach. Mit Hilfe der Biotestbatterie wird die Toxizit?t des Bodens differenziert beurteilbar; die boden-biologischen Befunde
lassen Langzeitwirkungen der TNT-Belastung wahrscheinlich werden. Eine Gesamtbeurteilung des Projekts wird im dritten Teil
der Artikelserie erfolgen.
OnlineFirst: 10. 09. 2001 相似文献
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The results presented in this report are based on analyses of 16,721 days of data downloaded from 96 archival tags recovered
from bigeye tuna (Thunnus obesus; 54–159 cm in length, 0.97–5.44 years of age) at liberty from 31 to 1,508 days in the equatorial eastern Pacific Ocean. Analyses
of daily timed depth and temperature records resulted in the classification of the data into three daily behavior types: characteristic,
associative (associated with floating objects), and other. There is a significant positive correlation between the proportion
of time fish exhibit characteristic behavior and increasing length, and significant negative correlations between the proportion
of time bigeye exhibit associative and other behavior with increasing length. For the smallest (54–80 cm) to largest (100–159 cm)
length classes, the vertical habitats utilized when exhibiting non-associative behaviors were 99 and 98% of the time above
the thermocline depth (60 m) during the night, at the same average depth of 34 m, and 60 and 72% of the time below the thermocline
during the day at average depths of 163 and 183 m, respectively. For the same smallest to largest length classes, when exhibiting
associative behavior, the average nighttime and daytime depths were 25 and 21, and 33 and 37 m, respectively. The apparent
effects of the environment on the behavior of the fish are discussed. 相似文献